In the related art, treatment tools that grip living body tissue to perform various kinds of treatment have been studied.
For example, in a grasping device described in Japanese Unexamined Patent Application, First Publication No. 2010-125200, an inner cylinder pipe is inserted into an outer cylinder pipe in a freely insertable manner, and an operating shaft is inserted through the inner cylinder pipe.
One end of a supporting member is anchored to a distal end of the operating shaft. A columnar body configured below a fixing clip is fitted into the supporting member. A combined state of the supporting member and the columnar body is released if both are slightly strongly pulled. A ring-shaped clip control body that abuts against a distal end of the inner cylinder pipe is provided inside the outer cylinder pipe.
The fixing clip is a plate-shaped body as a whole, and the aforementioned columnar body is formed integrally with a lower end of the fixing clip. A pair of movable clips are provided on both sides across the fixing clip. A root portion of each movable clip is anchored to a root portion of the fixing clip by welding. Each movable clip is made of materials having elasticity, and is biased in a direction in which the clip is opened with respect to the fixing clip. The root portion of each movable clip is provided with a protruding portion that overhangs outward. Each protruding portion is provided so as to be slightly shifted in a longitudinal direction of the fixing clip.
In the grasping device configured in this way, the outer cylinder pipe is pulled down with respect to the inner cylinder pipe, whereby the fixing clip and each movable clip are exposed from a distal end of the outer cylinder pipe, and each movable clip is opened. If the operating shaft is pulled down with respect to the inner cylinder pipe, the supporting member attached to the operating shaft also moves downward. According to the supporting member, the fixing clip and each movable clip also move downward. As the operating shaft is pulled down, the fixing clip and each movable clip move downward inside a central hole of the clip control body. However, as the protruding portion provided at a lower portion abuts against the edge of the central hole, the movable clip provided with the protruding portion moves to the fixing clip side, and holds one side portion of a large slit of tissue.
If the operating shaft is further pulled down, the other movable clip is moved to the fixing clip side by the same mechanism, and the other side portion of the slit is held. If the operating shaft is further pulled, the columnar body of the fixing clip slips out of the supporting member. Accordingly, the fixing clip and each movable clip remain inside the body in a state where the respective movable clips holding the side portions of the slip are biased in a direction in which the clip control body is closed.
Additionally, a grasping tool that grips stomach tissue is disclosed in Japanese Unexamined Patent Application, First Publication No. 2008-110210. A shaft and a pair of grasping jaw members are included in the grasping tool. Each grasping jaw member has a plurality of gear teeth. The gear teeth are configured so as to grip tissue. Each grasping jaw members is operable so as to be opened and closed via a cable.